Spring的扩展点有哪些

1、BeanFactoryPostProcessor

新建自定义的bean工厂的后置处理器MyBeanFactoryPostProcessor，交给Spring管理
MyBeanFactoryPostProcessor.java

package springextends;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.stereotype.Component;

@Component
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
	@Override
	public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
		// obtain the the beanFactory, you can do something that beanFactory allowed
		Person person = (Person) beanFactory.getBean("person");
		System.out.println("====before======="+ person.getName());
		person.setName("kebo");
		System.out.println("=====after======"+ person.getName());
	}
}

2、BeanDefinitionRegistryPostProcessor

BeanDefinitionRegistryPostProcessor是BeanFactoryPostProcessor的子接口
MyBeanDefinitionRegisterPostProcessor.java

package springextends;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.stereotype.Component;

@Component
public class MyBeanDefinitionRegisterPostProcessor implements BeanDefinitionRegistryPostProcessor {
	@Override
	public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
		System.out.println("before postProcessBeanDefinitionRegistry===All bean definition count is " + registry.getBeanDefinitionCount());
		registry.registerBeanDefinition("car", new RootBeanDefinition(Car.class));
		System.out.println("after postProcessBeanDefinitionRegistry===All bean definition count is " + registry.getBeanDefinitionCount());
	}

	@Override
	public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
		// do someting you want
	}
}

3、ApplicationLister

自定义事件监听器，ApplicationListener想监听什么事件就传入什么类型的ApplicationEvent
MyApplicationLister.java

package springextends_applicationListener;

import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

@Component
public class MyApplicationLister implements ApplicationListener<ApplicationEvent> {
	@Override
	public void onApplicationEvent(ApplicationEvent event) {
		System.out.println("received event is " + event);
	}
}